Split QtLocation into QtPositioning and QtLocation

QtPositioning is not dependent on any gui component and mostly
covers everything around the retrieval of position information.

QtLocation covers place, map and navigation APIs.

Several documentation issues were fixed during the process.

Change-Id: I98e2a53065549a2fc43f93a75b4f65b5bc884c92
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>